Automatic drain valve



FIG. 1 is a front view of an automatic drain valve in accordance with my new design;

FIG. 2 is a rear view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom view thereof; and,

FIG. 7 is a perspective view thereof.

The portions of the automatic drain valve shown in coarse dot pattern and outlined in dashed lines form no part of the claimed design. 

CLAIM The ornamental design for an automatic drain valve, as shown and described. 